Such safety sensitive edges are used wherever moving edges represent a safety hazard for persons or objects. As a rule, this relates to the closing edge of, for example, a gate or a door. Moreover, these safety sensitive edges are also used in mechanical engineering and plant construction. They ensure that that, in accordance with the respective Standards, mechanically moved edges are stopped or reversed when they encounter an obstacle. Such a safety sensitive edge is described, for example, in the European patent EP 0 833 287 B1.
In the case of a generic, optoelectronic safety sensitive edge, a light-transmitter device and a light-receiver device are coupled optically as well as electrically with one another. They are thus components of a feedback loop, which has, as further components, has at least one electrical coupling lead and an optical coupling section. The electrical coupling lead for conducting the electrical signal is scanned by an evaluating device, which generates from the scanned signal a release signal, which can be used, for example, for controlling a driving mechanism. Conventional optoelectronic safety sensitive edges indicate over the release signal whether or not the gate can be moved further. In this respect, the state of the art cannot indicate whether this safety sensitive edge has responded because there is an object in the path of the gate or whether the electrical coupling signal, scanned by the evaluating device, indicates a fault, because a component of the coupling section, such as a light transmitter or light receiver, is defective or has failed.